Threatened Green Sea Turtles: Feminization Linked to Hormone-Mimicking Pollutants

The research on green sea turtle populations suggests that specific pollutants accumulating in female turtles could be passed onto their offspring, potentially causing feminization.

This issue could exacerbate existing challenges for a species that already has fewer male hatchlings.

Dr. Arthur Barraza, a researcher at the Australian Rivers Institute at Griffith University, emphasized that green sea turtles are endangered due to various factors such as poaching, habitat destruction, and accidental capture in fishing gear.

He also highlighted the additional threat linked to climate change.

The study revealed that the number of male green sea turtles has been decreasing, as temperature-dependent sex determination results in more turtles developing as females with rising temperatures.

In some areas, such as the northern part of the Great Barrier Reef in Australia, the imbalance is significant, with hundreds of female turtles born for every male.

The research team collected eggs at a monitoring site on Heron Island in the southern Great Barrier Reef and studied the effects of pollution on the turtles’ development.

They found that contaminants, such as heavy metals and organic compounds, can mimic the hormone estrogen, potentially influencing the sex ratio of developing green sea turtles and biasing it towards females.

Dr. Jason van de Merwe, a marine ecologist and ecotoxicologist at the Australian Rivers Institute, explained that these contaminants, known as xenoestrogens, accumulate in female turtles at foraging sites and are absorbed by the developing eggs, affecting the hatchling sex ratios.

The study concluded that specific compounds in pollutants can change the sex ratios of hatchlings, emphasizing the importance of developing strategies to prevent pollutants from further feminizing sea turtle populations.

Dr. van de Merwe emphasized the need for science-based, long-term strategies to reduce pollutants entering the oceans, particularly heavy metals originating from human activities such as mining, runoff, and urban waste.

The research was part of the World Wildlife Fund for Nature – Australia’s Turtle Cooling Project.

When Do Sea Turtle Eggs Hatch?

The incubation period for most sea turtle eggs ranges from 50 to 70 days, and warm temperatures are required for the eggs to hatch within two months.

Baby sea turtles typically emerge from their eggs during the nighttime, between 9 pm and 5 am.

 Different species of sea turtles lay their eggs at different times, resulting in variations in the hatching periods around the world.

For example, leatherback sea turtles lay their eggs in Florida between March and August, so the baby leatherbacks should hatch between May and October.

Loggerhead sea turtles nest in June, and the nesting period extends into late July, resulting in hatching occurring in August and September.

Kemp’s Ridleys nest in Texas’s Gulf Shores between March and May, and their hatchlings emerge from the nests in late May or early July.

Green and hawksbill turtles visit the remote shores of the Parthenian Islands of Malaysia to lay eggs from late April to June, with the hatchlings breaking free from the eggs in late June and August.

The hatching times for sea turtles vary, but it is notable that most sea turtle eggs hatch in summer when the weather is warm. Learn more here, When Do Sea Turtle Eggs Hatch?

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